As the trend goes towards mobile internet, the complete internet protocol must be adopted in the mobile networks. A mobile terminal is assigned a unique IP-address so that data packets can be sent to the right terminal. The internet protocol has been used for a long time in fixed networks. There has not been need for mobility functionality until recently due to the new mobile devices with the possibility for packet switched data communications.
To provide the new functionality required by the mobility, a mobile internet protocol was introduced. The mobile internet protocol allocates two associated addresses for a mobile terminal: home address which enables the mobile terminal to be reachable with the same address regardless of its point of attachment and a care of address which enables to route the packets to the current point of attachment of the mobile terminal. This means that routing devices and transceiver stations of a mobile network must know and control the location of the mobile terminal and be able to efficiently route packets to the right terminal. At the moment, the IPv4 addressing scheme is in use but it will be replaced by the IPv6 in the future.
Within a radio access network (RAN) mobile terminals can move rapidly from one base station to another. A handover may occur when mobile stations move within a mobile network. When a mobile terminal moves from one base station to another, the routing must be changed. In the handover procedure, packets destined to the mobile terminals are directed to a base station. When the actual handover occurs packets will be directed to a new base station. This change must be fast to allow the data communication service continue at the selected quality of service. The handover can occur between similar network cells, for example from a GSM (Global System for Mobile communications) cell to another GSM cell, or between different type of networks, for example from a GSM network to a UMTS (Universal Mobile Telecommunications System) network.
New routing rules must be carried out within a mobile network for handover procedures. In routed networks, the routing rules are stored in routing tables. To change the routing table a routing table update message must be sent to all routers that the change effects to. The publication WO 0199458 introduces an efficient method for performing a mobile user terminal route update in a telecommunications network based on the internet protocol. The publication WO 0199458 teaches a method for updating the routing procedures. The method works in circuit and packet switched networks. In the method, a second base station sends new routing information to a routing element. The mobile device does not need to initiate the change of the routing tables. A benefit of the publication is that the router learns the new route early enough so that no data is lost in the handover procedure. The publication teaches the basic principles of the proxy localized management concept, in which the IP level local mobility management operations are hidden from the actual mobile device.
The drawbacks of prior-art solutions are that the modifications are needed to the terminal side and the signalling over the air interface. Required changes to already existing terminals are hard to implement. In cases where the changes cannot be implemented by software only, the customer needs to update his/her terminal.